Fix the spawning ratio
Fix the spawning ratio

The original game spawns a '2' block 90% of the time, while it spawns a '4' block 10% of the time.  Pulling to match this.
mevdschee/2048.c,byannoni/2048.c,lvfeng1130/2048.c,mevdschee/2048.c,byannoni/2048.c,lvfeng1130/2048.c